Normally desks or work stations are not height adjustable. Desk chairs usually are, but this is not ergonomically effective since chairs are usually height adjusted properly to position the seated user from the floor.
Some work tops utilize jack screws, either manually or power driven. These systems normally work in a vertical direction and require substantial force to move the work top to its desired position, especially if the work top is supporting fairly heavy equipment such as computers. Such gear or screw systems are most commonly used in free standing tables and such systems must normally have a mechanical link between the two sides or legs since the lift must be equal on both sides. This further contributes to friction loss, cost and inefficiency within the system.
Another problem has to do with the weight of the top itself and what is supported thereon. As the weight or size becomes larger, the weight increases considerably and the mechanism developed for one size may work less well for a larger or heavier top. Also, if the system is designed for heavier loads, it is neither efficient nor cost effective for lighter loads.
Since even the smallest surface may have to lift the weight of a heavy computer, very high ratio gearing is normally employed. This creates another problem when a crank is used. It simply takes a lot of cranking. A motor, or motors, will do the job well enough, but lead to higher cost, possible noise and always the possibility of breakdown.
Another solution has been the use of hydraulic or gas cylinders. Once again the problem of a variety of weights of tops and loads makes selection of the components difficult. With a gas lift, while it lifts the surface with ease, the user must normally stand up and use his weight to force the top down. This is obviously easier for some people than for others. Moreover, gas cylinders are expensive and are prone to breakdown. Further, if more than one is used, it simply doubles the problems created by one.
In an open office beam system, such as manufactured by SunarHauserman of Cleveland, Ohio, under the trademark RACE, one or more work surfaces may be mounted on such beams to extend in cantilever fashion, and for longer or larger work surfaces they may additionally be supported on one or more outboard legs. Such beams are normally supported on legs at each end and may be height adjusted, again by manual jack screws. Also, the outboard legs of the longer or larger work tops may be height adjusted, usually by jack screws at their feet. Such height adjustment, at best, represents a compromise since the beam may support one or more additional work tops and such height adjust system is, needless to say, cumbersome. If a work top is attached to a panel or partition, it often requires two people with tools to change the work height. The result in such systems is that work surfaces tend to be set at a certain height and left there since a change in height would represent more effort than benefits gained.
It is therefore desirable to have a work top, either free standing, panel, partition, or beam mounted, which may quickly manually and conveniently be height adjusted by a simple spring compensated horizontal force at the work top height.